1. Field of the Invention
The present invention generally relates to an air-guiding casing of a ventilation fan and, more particularly, to an air-guiding casing of a ventilation fan having a detachable air-guiding tube.
2. Description of the Related Art
FIG. 1 shows a conventional air-guiding casing 9 including a main body 91 and an air-guiding tube 92 affixed to the outer periphery of main body 91. Main body 91 includes a compartment 911 and an air inlet 912 in communication with compartment 911. Air-guiding tube 92 includes an air outlet 921 in communication with compartment 911. In this arrangement, an impeller can be received in compartment 911 of main body 91. An alternating current (AC) or direct current (DC) motor is used to power the impeller so that the impeller can be operated to draw air into compartment 911 via air inlet 912 and to discharge air from compartment 911 via air outlet 921. As such, a desired ventilation effect can be provided. Taiwan Patent No. M391590 discloses a similar air-guiding casing.
However, air-guiding casing 9 has a drawback that main body 91 and air-guiding tube 92 cannot be easily detached from each other. In this regard, when it is desired to replace the impeller (or the air-guiding tube 92) with another one having a different size, the entire air-guiding casing 9 must be changed. In other words, it is impossible to change only the main body 91 or the air-guiding tube 92. This results in an inconvenience in use and increases the cost. Therefore, it is necessary to improve the conventional air-guiding casing 9.